Stream out & Stream in: Virtuoso

Hi
I'm using Cadence virtuoso layout editor, I want to stream out and
stream In the GDS with preserving properties like "connectivity" and
"property" . Right now, i'm loosing those connectivity information
when i stream out GDS and stream In back. Could some help me in this
regard.

Thanks,
Kitty Movva.

 

Kitty Movva wrote, on 01/24/10 12:17:

Hi Kitty,

You can keep pin information by storing it as an attribute, but the Virtuoso
stream interface does not annotate connectivity information for nets.

Fundamentally stream format (aka GDS) does not store connectivity data, and
various people have utilized attributes on the objects to represent the
connectivity data.

Why do you need to stream out and back in again? Wouldn't it be better to keep
the original design database?

Regards,

Andrew.

 

Hi Andrew,
Thanks for reply.
Basically, i'm getting GDS from Encounter streamout. I'm streaming In
the GDS in to virtuoso environment. I'm getting connectivity
information as property. But, when i streamout and streamin this GDS
through virtuoso, i'm loosing that info. Can you tell me how to keep
pin information by storing it as an attribute.

Thanks,
Kitty Movva

 

Kitty Movva wrote, on 01/25/10 13:08:

Hi Kitty,

That's covered in the documentation - I don't have time to look it up for you
right now. There are also solutions on support.cadence.com :

http://sourcelink.cadence.com/docs/db/kdb/2002/Sept/11049566.html
http://sourcelink.cadence.com/docs/db/kdb/2002/Apr/11017652.html
http://sourcelink.cadence.com/docs/db/kdb/2000/Nov/1840440.html

However, if you're going from Encounter into virtuoso, then you would be better
off using the LEF/DEF route or if you're using IC613/IC614, then you could just
save an OA database directly from Encounter and open it in virtuoso, without
loss of information. You can then edit it in Virtuoso (provided you follow the
rules - also covered in the documentation somewhere) and reopen it in Encounter.
This is the whole "MSoT" (Mixed Signal on Top) flow.

DEF also contains the connectivity information, so that is better.

Regards,

Andrew.

 

HI Kitty - LEF/DEF is the best solution but if you must use GDS, you
can typically regain the connectivity
by:

1) creating pins from labels then do an update components
2) connectivity-->update connectivity and nets
3) connectivity-->re-extract layout.

Rick